Question about possibilities in logic

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Mattchew83
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Question about possibilities in logic

Post by Mattchew83 »

Must we prove a possibility logically in order for it to be considered a possibility? Or is something possible if nobody can disprove the proposed possibility? Please explain logically. Thanks.

At this time, I believe in the later.
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Terrapin Station
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Re: Question about possibilities in logic

Post by Terrapin Station »

The most common take on this is:

"X is logically possible just in case x is not logically impossible, where 'logically impossible' refers to being or entailing a logical contradiction, and we're in a non-paraconsistent logic."
Mattchew83
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Re: Question about possibilities in logic

Post by Mattchew83 »

Terrapin Station wrote: Sat Jan 15, 2022 1:06 am The most common take on this is:

"X is logically possible just in case x is not logically impossible, where 'logically impossible' refers to being or entailing a logical contradiction, and we're in a non-paraconsistent logic."
Thanks for your response. I agree.

What can be said about those who present possibilities without supporting reason?

For example:

Person 1: "Global warming is real" (without any reason (proven or unproven))

Person 2: "Global warming is real because temperatures have been rising over the past 20 years" (with reason although unproven).

Can we say that person 1 is illogical in the case that they are unable to provide any reason? Please explain logically.
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Terrapin Station
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Re: Question about possibilities in logic

Post by Terrapin Station »

Mattchew83 wrote: Sat Jan 15, 2022 6:10 pm
Terrapin Station wrote: Sat Jan 15, 2022 1:06 am The most common take on this is:

"X is logically possible just in case x is not logically impossible, where 'logically impossible' refers to being or entailing a logical contradiction, and we're in a non-paraconsistent logic."
Thanks for your response. I agree.

What can be said about those who present possibilities without supporting reason?

For example:

Person 1: "Global warming is real" (without any reason (proven or unproven))

Person 2: "Global warming is real because temperatures have been rising over the past 20 years" (with reason although unproven).

Can we say that person 1 is illogical in the case that they are unable to provide any reason? Please explain logically.
Logic isn't at all the same thing as rhetoric. You're talking more about rhetoric. Logic is basically "what follows from what."
Mattchew83
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Re: Question about possibilities in logic

Post by Mattchew83 »

Terrapin Station wrote: Sat Jan 15, 2022 7:39 pm
Mattchew83 wrote: Sat Jan 15, 2022 6:10 pm
Terrapin Station wrote: Sat Jan 15, 2022 1:06 am The most common take on this is:

"X is logically possible just in case x is not logically impossible, where 'logically impossible' refers to being or entailing a logical contradiction, and we're in a non-paraconsistent logic."
Thanks for your response. I agree.

What can be said about those who present possibilities without supporting reason?

For example:

Person 1: "Global warming is real" (without any reason (proven or unproven))

Person 2: "Global warming is real because temperatures have been rising over the past 20 years" (with reason although unproven).

Can we say that person 1 is illogical in the case that they are unable to provide any reason? Please explain logically.
Logic isn't at all the same thing as rhetoric. You're talking more about rhetoric. Logic is basically "what follows from what."
So you are saying that person 1's statement is considered rhetoric? So in order for a statement to be reasonable and considered a possibility it must be accompanied by reason?
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Terrapin Station
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Re: Question about possibilities in logic

Post by Terrapin Station »

Mattchew83 wrote: Sun Jan 16, 2022 1:26 am
Terrapin Station wrote: Sat Jan 15, 2022 7:39 pm
Mattchew83 wrote: Sat Jan 15, 2022 6:10 pm

Thanks for your response. I agree.

What can be said about those who present possibilities without supporting reason?

For example:

Person 1: "Global warming is real" (without any reason (proven or unproven))

Person 2: "Global warming is real because temperatures have been rising over the past 20 years" (with reason although unproven).

Can we say that person 1 is illogical in the case that they are unable to provide any reason? Please explain logically.
Logic isn't at all the same thing as rhetoric. You're talking more about rhetoric. Logic is basically "what follows from what."
So you are saying that person 1's statement is considered rhetoric? So in order for a statement to be reasonable and considered a possibility it must be accompanied by reason?
I'm saying that what you're talking about in general, that you want supporting reasons for a claim being made, otherwise we shouldn't bother considering the claim, etc. etc. is about rhetoric, not logic.

Rhetoric "aims to study the techniques writers or speakers utilize to inform, persuade, or motivate particular audiences in specific situations . . . Rhetoric typically provides heuristics for understanding, discovering, and developing arguments for particular situations." So it's strictly rhetoric, and not the logical aspects of rhetoric, that we're concerned with when we're worried about people stating reasons or not for what they're arguing, when we're worried about whether the reasons are plausible, persuasive, etc.

It's not that good rhetoric won't involve logic, but logic is strictly the notion of "what follows from what," under the particular logic at hand (there are different species of logic; different species can have incompatible, even contradictory features relative to other species). Logic has to do with things like "assuming that P and Q are the case, what necessarily follows?" In other words, it's what P or Q imply, given the stipulations of the particular species of logic at hand. Logic isn't really worried about whether P and Q actually ARE the case, and logic can not tell us whether P and Q actually are the case. Logic is only concerned with _what follows_ from P and Q, assuming they are the case. Logic can be seen as the "science of implication" (though using "implication" very broadly so that it includes deduction, induction, abduction, inference, etc.)

Rhetoric is much broader--and much vaguer, than logic. Rhetoric can just as well be seen as an artform more or less, which is why literature departments tend to teach it just as much as philosophy departments.
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